Dementia is a serious medical, public health and social problem that requires criteria for early identification by differentiating between early dementia memory impairment (EDMI) and age-associated memory impairment (AAMI). Long-term objectives are to study mechanisms of memory impairment in AAMI and EDMI and validate clinical criteria for EDMI and AAMI. Specific aims are to (1) identify EDMI by discrepancy between predicted and observed memory in the ICR Double Memory Test, (2) assess the changes of memory and other cognitive abilities in AAMI and EDMI, (3) account for memory changes in AAMI and EDMI by impairment of specific cognitive processes, and (4) validate criteria for EDMI and AAMI by repeated assessment in long-term follow-up. Specific hypotheses are that EDMI can be differentiated from AAMI by performance scores on the Category ICR memory test that are significantly lower than predicted from performance on the Item ICR memory test; that AAMI can be identified by changes reported in the memory and cognitive history (MacHistory) that result in more frequent memory lapses which are still qualitatively similar to those of young adults; that EDMI can be discriminated from AAMI by changes reported in the MacHistory which are qualitatively as well as quantitatively different from those in AAMI; that criteria for AAMI and EDMI can be enhanced by information from the MacHistory about changes in personal memory and kinds of memory lapses in the real world. Regression analyses will be done to explain changes in AAMI and EDMI by changes of specific cognitive processes in tests of attention, processing capacity, cognitive speed, serial-order learning, and forgetting. The results will provide information needed for more specific earlier diagnosis of AAMI and EDMI, for pharmacologic testing and treatment, and to correlate changes in AAMI and EDMI with physiologic, biochemical and pathologic changes in aging.